Ship and vessel inspection robots: which robot suits which space, and what the rules allow

Yes, and the classification societies have said so in writing for a decade. IACS Recommendation 42, “Guidelines for Use of Remote Inspection Techniques for surveys”, lists divers, unmanned robot arms, remotely operated vehicles, climbers, drones and “other means acceptable to the Society” as remote inspection techniques that, when permitted, may be used to facilitate the required external and internal examinations, including close-up surveys and thickness gauging. The condition that matters is in the same document: the results are to be acceptable to the attending surveyor. A robot does not replace the survey; it changes how the surveyor gets the evidence, and the surveyor still decides.

In practice that has produced three mature robot forms on ships, aerial drones for tanks and holds, magnetic crawlers for hull plating and thickness, and ROVs for the underwater hull, and one emerging form, the legged robot, for the parts of a ship that are laid out for people: machinery spaces, corridors, stairways and decks. Each answers a different inspection question.

Classification surveys

IACS Recommendation 42 is the common framework the member societies work from. Its position is permissive but conditional: remote inspection techniques may be used to facilitate required examinations, including close-up surveys and gauging, when permitted, and the results are to be acceptable to the attending surveyor when used towards crediting a survey. Each society publishes its own rules and, in several cases, approves the firms that carry out remote inspection on its behalf. The practical consequence for an operator is that a robotic survey is planned with the class surveyor, not presented to them afterwards.

Confined spaces in the UK

Ashore, the Confined Spaces Regulations 1997 apply: entry must be avoided where reasonably practicable, and where it cannot be avoided, a safe system of work and emergency arrangements are required. The Health and Safety Executive’s guidance treats sending a machine in instead of a person as the first option in that hierarchy. At sea, the Merchant Shipping regulations on entry into dangerous spaces and the vessel’s own safety management system apply. A robot that inspects a tank without a person entering it is not a convenience; it is the avoidance the law asks for first.

Gas, explosive atmospheres and Ex zones

Spaces that may hold flammable gas or vapour, cargo tanks, pump rooms, fuel and LNG-related spaces, are zoned, and only certified equipment goes in. The relevant certifications are ATEX in the UK and EU and IECEx internationally. Among the platforms in the quadruped class, only ANYbotics publishes an Ex-certified variant, ANYmal X, certified ATEX and IECEx for Zone 1 IIB. Every other quadruped on the market is uncertified for hazardous atmospheres and stays outside the zone. Gas detection is a payload question in every case: the sensors an operation needs, lower explosive limit, oxygen and hydrogen sulphide as a minimum, have to be fitted, rated and calibrated, and a maker’s claim that a robot “identifies gas leaks” should be read with the sensor list beside it.

A ship’s machinery spaces, corridors and decks are laid out for people: stairs with handrails, sills and coamings at every watertight door, gratings over bilges, and equipment that expects a human eye at a gauge. That is ground a wheeled robot cannot cover and a drone cannot dwell in, and it is the case for legs. The realistic job is the routine round: the same route, the same viewpoints, every watch, with a thermal camera on bearings and switchboards, a zoom camera on gauges and sight glasses, a microphone for the sound of a pump that is about to fail, and gas sensors where the space needs them. Consistency is the value. The same viewpoint every pass means change stands out, and a person is sent to look only when something has changed.

The robot is the carrier; the sensors do the inspection. For machinery-space rounds the set that earns its place is a thermal camera for bearings, motors, switchboards and pipe temperatures; a zoom camera for gauges, sight glasses and leak evidence; a microphone or acoustic sensor for pumps and compressors; gas detection matched to the space, lower explosive limit, oxygen and hydrogen sulphide at minimum, and rated for the zone; and lighting, because many spaces are dark when unattended. For structural work the crawler’s ultrasonic thickness gauge and the drone’s close-up camera are the established tools, and the class surveyor will say what resolution and coverage they accept.

On the industrial quadrupeds these sensors are a payload or a configuration: Spot Cam 2 on Spot with thermal and 25× zoom; the standard pan-tilt unit on ANYmal with a 20× zoom, a thermal camera rated for −40 to 550 °C, a spotlight and an ultrasonic microphone; configuration on the DEEP Robotics X30 and Unitree B2, whose makers do not itemise the standard sensor suite. Each payload adds weight against the robot’s rating and must be rated for the environment itself.

Alongside, on one route, with the class surveyor and the safety management system in the room from the start. Choose the space and the inspection first, then the robot form from the table above, then the platform from its published ratings. Agree the measures before anything goes aboard: coverage of the intended round, the observations captured against a human round of the same route, the sills and stairs cleared, the behaviour when the link dropped, operator time per round, and whether the data reached the maintenance system in a form the crew used. Include an exit condition. Then run it repeatedly, through wash-downs and through the worst weather available at the berth.

That is how we structure a pilot programme, on a manufacturer-neutral basis, and where engineering delivery needs scale we work through our engineering delivery partnership. The generic checks for any quadruped pilot are in our guide to quadruped robot inspection in the UK, and the question of getting the robot’s observations into the systems a ship already runs is in integrating a robot with the software you already have.